Name:
Hertzsprung-Russell Diagram
Instructions:

Go to the following website: http://aspire.cosmic-ray.org/Labs/StarLife/hr_diagram.html. Read
the ENTIRE webpage before continuing.

Click on the Interactive Lab and fill out the HR diagram. Check your answers by clicking the
CHECK button. Once you have every answer correct, fill in the Diagram provided to you on the
attached sheet. (You may see this diagram in the future ;).

In the top right corner of the webpage is an arrow to move on to a new page. Click that arrow,
and then click on the interactive picture to begin the interactive activity. As you complete the
interactive activity fill out questions related to the various sections of the activity. For example,
question number one is associated with the first section of the activity (Hypothesis Background).
1. Which Hypothesis would match the Hypothesis Background? (1 or 2) Explain why your answer is
correct.
2. The Sun is a main sequence star. Where would you expect to find other main sequence stars of
the same size on the diagram given? (1,2,or 3). BONUS: On which color line would our sun be on
when it’s in the red giant stage?
3/4. What can the curved main sequence line tell us about main sequence stars that have a
different mass than the sun?
5. True or False: Different Stars have different masses.
6. True or False: Stars with a mass of about 10 Msun will have almost all of the same
characteristics as other stars near 10 Msun.
7. True or False: The most massive stars shine very dimly in comparison with other smaller stars.
8. The majority of a star’s life cycle is spent as a main sequence star. Why is that true?
9. The surface temperature and brightness of a star changes drastically over the course of a stars
life. Why is that true?
10. A star with a large mass will radiate more energy into space and appear hotter and brighter
than a star with a smaller mass. Why is this true (Part of your explanation for number 9 is the
key for this question)
11. True or false: Smaller mass stars have a greater luminosity than larger mass stars. What are
the exceptions?